package com.sy.hello;


import java.util.HashSet;
import java.util.TreeSet;

public class HelloWorld {
    public static void main(String[] args) {
        TreeSet treeSet = new TreeSet();
        treeSet.add(new A());
        System.out.println("爱莉希雅");
    }

}


class A {
    void Hi() {
        System.out.println("Hi");
    }
}

class B extends A {
    void Hello() {
        System.out.println("Hello");
    }
}
